1. Field of the Invention
The present invention pertains to the art of rotary cutting machines and, more particularly, to a blade holding assembly for such a machine.
2. Discussion of the Prior Art
There exists various types of rotary cutting machines incorporating blades which need to be disconnected from a drive source in order to be periodically replaced or sharpened. For example, lawn mower blades should be sharpened or replaced at least yearly for peak effectiveness. In general, removing a lawn mower blade requires somehow retaining the blade from rotating while removing a retaining bolt used to drivingly interconnect the blade to an engine shaft. Removing a blade retaining bolt can often be difficult, and even dangerous. In fact, it is not uncommon for a retaining bolt to be over tightened or even rusted in place.
Regardless of the condition of the retaining bolt, it is necessary to prevent the blade from rotating while the high torque necessary to loosen the bolt can be applied, generally through the use of a wrench. Oftentimes, when changing a blade on a lawn mower, a block of wood, a brick or other handy object is initially placed between the blade and a discharge chute or other deck portion of the mower to prevent the blade from shifting as the bolt is being rotated. If the object slips, a cut or bruised hand may result. In addition, these types of arrangements can result in the potentially dangerous condition of blade kickback, particularly if the blade is only held against rotation in one direction. As an alternative, one can resort to utilizing leather work gloves for holding a blade secure while the bolt is loosened. This type of arrangement is not always effective as merely grasping the end of the blade with a gloved hand may not enable sufficient leverage to be developed to enable an overly tightened or rusted bolt to be removed. In addition, depending upon the condition of the blade and the quality of the gloves, this operation may be hazardous.
The problems associated with removing or installing a blade on a lawn mower can be further compounded by the ground level location of the blade. That is, the blade may only be limitedly visible and accessible through the discharge chute unless the mower is run up on blocks, elevated on jacks, tilted backwardly or turned upside down. Although a push-type lawn mower can be fairly easily placed on its side to enhance access to the blade, the same is not possible in connection with a riding lawn mower. Oftentimes, even a heavy riding lawn mower is not elevated on blocks just to remove or install a blade. Instead the mower deck is simply elevated as far as possible which generally provides about 5 inches (approximately 12.5 cm) of visibility and working space for a person lying or crouching on the ground.
Regardless of the degree of accessibility of the blade, changing a blade simply represents a potentially dangerous endeavor, particularly due to the problem of adequately preventing the blade from undesirability rotating. Therefore, providing a safe and effective system for changing a blade of a rotary cutting machine, i.e., either replacing a blade or removing it for sharpening and then reinstalling the same, is considered an important issue which needs to be addressed in connection with lawn mowers, as well as other rotary cutting machines.
Based on the above, there exists a need in the art for a blade holding system which can be effectively used to either remove or mount a blade to a rotary cutting machine under a wide range of conditions. More particularly, there exists a need for an arrangement which provides for maintaining a rotatable blade in a fixed position in a hands free manner such that an extremely safe system is provided. In addition, there exists a need for such a blade changing arrangement wherein the structure for holding the blade is advantageously carried by the machine so as to be readily available, while being conveniently movable to an unobstructing storage position when not needed.
The present invention is directed to a blade holding assembly for use in changing a blade of a rotary cutting machine. More specifically, the blade holding assembly includes a blade fixing element which can be selectively moved between a storage condition, wherein the blade fixing element is mounted to the machine in an unobtrusive position, and an in-use condition, wherein the blade fixing element is remounted in a position which obstructs the rotation of the blade. More specifically, in the in-use condition, the blade fixing element preferably projects through or otherwise engages the blade to prevent the blade from rotating in either direction. In accordance with the most preferred form of the invention, the blade fixing element is adapted to extend through a hole provided in the blade to secure the blade against rotation in a hands free manner.
The present invention is particularly applicable for use in connection with installing or removing the blade of a lawn mower. The blade holding assembly can be readily incorporated into the manufacture of new rotary cutting machines or supplied as a retrofit attachment. In accordance with one preferred embodiment of the invention, the blade holding assembly includes an easily gripped blade fixing element in the form of a partially threaded rod which can be selectively shifted to project either above the deck of a lawn mower in a storage condition or below the deck and through a mower blade in an in-use condition.
Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of preferred embodiments thereof when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.